The lower-case letter γ has a number of uses in maths and sciences, for example:
- in astronomy: the third brightest star in a constellation. For instance, Bellatrix is designated as γ Orionis.
- in inorganic chemistry: a symbol for certain allotropes, for example γ-iron (austenite) or γ-sulfur
- in mathematics: the Euler—Mascheroni constant, a mathematical constant with approximate value of 0.57721
- in organic chemistry: γ-carbon, the third carbon atom in a chain when counting from a functional group. The names such as γ-aminobutyric acid (GABA) make use of this nomenclature.
- in neurophysiology: γ-waves, a type of brain waves detected by electroencephalography
- in phonetics: voiced velar fricative (IPA symbol ɣ)
- in physics: γ is the symbol for a photon, probably derived from γ-rays or γ-radiation, a kind of electromagnetic radiation arising from the radioactive decay (γ-decay)
- in special relativity: Lorentz factor